1. Field of the Invention
The present invention relates to a multi-link type suspension system including a knuckle for rotatably supporting an axle, five arms for connecting the knuckle to a vehicle body for vertical movement, and a damper for buffering the vertical movement of the knuckle.
2. Description of the Prior Art
Such a multi-link type suspension system has been already known as disclosed in Japanese Patent Application Laid-open No. 134309/82.
As shown in FIG. 12, the above multi-link type suspension system includes an upper arm UP and an upper trailing arm UTR for connecting a knuckle N with a vehicle body B above an axle A, as well as a lower arm LO and a lower trailing arm LTR for connecting the knuckle N with the vehicle body B below the axle A, and a control arm CO for connecting the knuckle N with the vehicle body B in front of the axle A.
In general, in suspension systems, it is desirable for purpose of enhancing the steering stability to have a tendency of a toe-in, i.e., a tendency for a front end of the wheel to be offset inwardly of the vehicle body during braking. However, the prior art multi-link type suspension system suffers from a problem that a proper toe-in cannot be produced by a braking force.
More specifically, in the prior art multi-link type suspension system, as shown in FIG. 13A, a portion of the knuckle N above the axle A, i.e., outer ends of the upper arm UP and the upper trailing arm UTR are swung in a direction indicated by c' about an outer end of the control arm CO to produce a toe-in tendency. In addition, as shown in FIG. 13B, a portion of the knuckle N below the axle A, i.e., outer ends of the lower arm LO and the lower trailing arm LTR are swung in a direction indicated by f' about the outer end of the-control arm CO to produce a toeing-out tendency. Therefore, a reverse force is applied to the portions of the knuckle N above and below the axle A, whereby the rear wheel W cannot be properly toed-in with braking.